1. Field of the Invention
The present invention relates to a heat exchanger support structure of a motor vehicle which supports a heat exchanger, such as a radiator, on a motor vehicle body, for example, at its front structure.
2. Description of the Related Art
A heat exchanger support structure of a motor vehicle of this kind is disclosed in, for example, Japanese patent laying-open publication No. (Tokkai) 2003-81135, which illustrates only a radiator core support.
The radiator core support mainly comprises an upper radiator core support member extending laterally with respect to a motor vehicle body, a lower radiator core support member in parallel with and vertically apart from the upper support member, a hood lock stay connecting the center portions of the upper and lower support members with each other, and right and left side support members respectively connecting the upper and lower sides of the upper and lower support members with each other, which are made of steel or aluminum alloy.
The lower support member has an enclosed rectangular cross section and is provided on its upper surface with two lower supporting portions to be laterally separated from each other. The lower supporting member supports a radiator core as a heat exchanger on the lower supporting portions. The upper support member also supports the radiator core similarly to the lower support member. The radiator core support, supporting therein the radiator core, is mounted to a front structure of a motor vehicle body.
In recent years, a radiator core support that has a configuration similar to the above radiator core support and is mainly made of resin is increasing in use for saving weight and its design freedom. In this case, a lower radiator core support member is formed of resin by injection molding to have a cross-sectional shape like a channel that opens rearward for weight saving and easy removal of the molded support member from the mold. The lower support member comprises an upper portion, a lower portion in parallel with the upper portion, and a front vertical wall portion connecting the upper and lower portions with each other. The upper portion is provided on its upper surface with two lower supporting portions laterally separated from each other. The lower support member supports the radiator core on its upper side portion.
The above known conventional heat exchanger support structure of a motor vehicle, however, encounters a problem in that the channel shaped lower support member fails to maintain satisfactory rigidity of the lower supporting portion against a shearing force caused by the radiator core's weight and/or a load fluctuation during vehicle running for a long time.
In order to avoid the above described problem, there have been various attempts, for example, to add as many ribs as possible to weak rigidity portions of the lower radiator core support member, or to position the lower supporting portion as close as possible to the vertical wall portion. The former attempt, however, increases the weight and cost, and the latter the space for installing the radiator.
It is, therefore, an object of the present invention to provide a heat exchanger support structure of a motor vehicle which overcomes the foregoing drawbacks and can strengthen the rigidity, at a lower supporting portion of a lower heat exchanger support member made of resin, against shearing stress caused by weight of a heat exchanger to reduce deformation thereof.